In the manufacture of torsion type coil springs conventional front and/or rear tails can be formed with the aid of the auxiliary drive and a movable coiling tool of the usual type having active and inactive positions at the coiling station adjacent the line of wire feed. Front and rear tail "start" sensors are provided on the machine camshaft together with the aforementioned end position "start" sensor. Front and rear tail "stop" sensors and an "index" sensor respond to auxiliary drive and speed reducer output and bistable "on" - "off" devices are provided respectively for servo motor forward and reverse drive operation. In front tail formation, the corresponding camshaft sensor starts servo motor forward drive operation with the coiling tool inactive and the tail is formed with wire feeding operation terminated by the front tail "stop" sensor on the servo motor output. The main body of the spring may then be formed with the coiling tool in its active position and with the main and auxiliary drives operating sequentially as mentioned and with the front tail precisely positioned. Auxiliary drive operation with the coiling tool inactive may thereafter be initiated by the rear tail "start" sensor on the camshaft, terminated by the rear tail "stop" sensor on the servo motor output, and reverse drive indexing accomplished by the rear tail "stop" and the "index" sensor.
THE PRESENT INVENTION RELATES TO THE GENERAL TYPE OF SPRING COILING MACHINE WHEREIN WIRE IS FED ALONG A LONGITUDINAL PATH INTERMITTENTLY AND IS COILED DURING FEEDING BY A COILING TOOL OR ABUTMENT TO FORM SPRINGS, CUT-OFF OCCURRING AT THE END OF EACH WIRE FEEDING AND COILING OPERATION. While not necessarily so limited, the invention is particularly applicable to spring coiling machines of the type shown in:
U.s. pat. No. 2,119,002 issued May 31, 1938 to Bergevin and Nigro. PA1 U.s. pat. No. 2,455,863 issued Dec. 7, 1948 to E. W. Halvorsen. PA1 U.s. pat. No. 2,820,505 issued Jan. 21, 1958 to E. E. Franks et al. PA1 U.s. pat. No. RE24,345 issued Aug. 20, 1957 to C. R. Bergevin. PA1 U.s. pat. No. 2,902,079 issued Sept. 1, 1959 to Costello et al. PA1 U.s. pat. No. 2,923,343 issued Feb. 2, 1960 to Franks. PA1 U.s. pat. No. 2,925,115 issued Feb. 16, 1960 to Franks. PA1 U.s. pat. No. 3,009,505 issued Nov. 21, 1961 to Franks. PA1 U.s. pat. No. 3,068,927 issued Dec. 18, 1962 to Bergevin. PA1 U.s. pat. No. 3,402,584 issued Sept. 24, 1968 to Cavagnero. PA1 U.s. pat. No. 3,934,445 issued Jan. 27, 1976 to Lampietti.
More particularly, the invention relates to a spring coiling machine of the general type mentioned wherein provision is made for the precise control of wire end and/or tail position and for the forming of torsion type coil springs.